Final Exam CHEM 219 Latest Update 2025-2026
120 Questions and 100% Verified Correct
Answers Guaranteed A+
_________ is a measure of the tendency of a material to change into the gaseous state
- CORRECT ANSWER: Vapor pressure is a measure of the tendency of a material to
change into the gaseous state. The molecules are moving rapidly and if they have
enough energy they will escape from the liquid.
(NH₄)₂SO₄ has a van't Hoff factor of i = 2.3. What is the concentration of particles in a
0.7801 M solution of (NH₄)₂SO₄? - CORRECT ANSWER: 1.8 M
2.3 x 0.7801 = 1.8
M=(i)x(M)
A bond in which an electron pair is unequally shared by two atoms is
A) ionic.
B) polar covalent.
C) nonpolar covalent.
D) coordinate covalent.
E) dipolar. - CORRECT ANSWER: B) polar covalent.
A solution is made by dissolving 2.5 mg sodium fluoride (NaF) in 1.5 L of water at
20.0°C. What is the fluoride ion concentration in ppm of the resulting solution, given that
NaF is 45.0% fluoride ion by mass, and the density of water of 1.00 kg/L? - CORRECT
ANSWER: 2.5 x 45/100 = 1.125mg
weight of ion / weight of water = ppm
so, 1.5L = 1.5 Kg
1.125mg / 1.5 kg = 0.75
,A solution is made using 163.7 g of dimethyl ether (MM = 46.07 g/mol) and 90.0 g of
methanol (MM = 32.04 g/mol). What is the mole fraction of the dimethyl ether in the
solution? - CORRECT ANSWER: find mol of dim & methanol
dim mol / dim mol + methanol = mol fraction
A solution is made using 175.7 g of hexane (MM = 86.18 g/mol) and 200.0 g of octane
(MM = 114.2 g/mol). What is the molality of the hexane in the solution? - CORRECT
ANSWER: m = (W g of solute / Molar mass of solute) (1000 / W g of solvent)
(175.7g / 86.18g/mol) ( g) = 10.19m
A theory is another word for a(n) _________. - CORRECT ANSWER: A theory or model
is a well established explanation of a phenomenon based on a series of facts and a
body of evidence.
All the following statements concerning a sample of oxygen gas at 1.00 atm pressure
are true EXCEPT
A) the molecules are in constant rapid random motion.
B) the pressure exerted by gaseous oxygen is due to the impact of the molecules with
the walls of the container.
C) the average kinetic energy of the gaseous oxygen is inversely proportional to the
absolute temperature of the gas.
D) collisions between the gaseous molecules are elastic.
E) the volume occupied by the oxygen molecules is negligible compared with the size of
the container. - CORRECT ANSWER: C) the average kinetic energy of the gaseous
oxygen is inversely proportional to the absolute temperature of the gas.
All will contribute equally. Because boiling point elevation is a colligative property, it
depends only on the concentration of solute, not the type of solute. - CORRECT
, ANSWER: Vapor pressure describes the tendency of a substance to change from the
liquid to the gas phase, so substances with weaker intermolecular forces will have
higher vapor pressures. A substance's boiling point is also indicative of the strength of
the intermolecular forces, with weaker intermolecular forces resulting in lower boiling
points. Because acetone has the lowest boiling point of the options given, it has the
weakest intermolecular forces, and will therefore have the highest vapor pressure.
Amonton's Law - CORRECT ANSWER: if the volume of a gas is held constant,
increasing the temperature of the gas increases its pressure.
An exothermic reaction causes the surroundings to - CORRECT ANSWER: An
exothermic reaction transfers energy from the system to the surroundings. That tells us
the surroundings will get warmer.
At a particular temperature, the solubility of H₂ in water is 0.140 M when the partial
pressure is 1.20 atm. What partial pressure (in atm) of H₂ would give a solubility of 4.95
M? - CORRECT ANSWER: 42.4 atm
C = kP --> c12/c1 = p2/p1
Avagadro's Law
in terms of KE - CORRECT ANSWER: Container pressure constant, more gas
molecules added = increased volume
Avogadro's Law - CORRECT ANSWER: equal volumes of gases at the same
temperature and pressure contain equal numbers of molecules
Boyle's Law
in terms of KE - CORRECT ANSWER: Volume decreased, wall area decreased =
increased pressure
120 Questions and 100% Verified Correct
Answers Guaranteed A+
_________ is a measure of the tendency of a material to change into the gaseous state
- CORRECT ANSWER: Vapor pressure is a measure of the tendency of a material to
change into the gaseous state. The molecules are moving rapidly and if they have
enough energy they will escape from the liquid.
(NH₄)₂SO₄ has a van't Hoff factor of i = 2.3. What is the concentration of particles in a
0.7801 M solution of (NH₄)₂SO₄? - CORRECT ANSWER: 1.8 M
2.3 x 0.7801 = 1.8
M=(i)x(M)
A bond in which an electron pair is unequally shared by two atoms is
A) ionic.
B) polar covalent.
C) nonpolar covalent.
D) coordinate covalent.
E) dipolar. - CORRECT ANSWER: B) polar covalent.
A solution is made by dissolving 2.5 mg sodium fluoride (NaF) in 1.5 L of water at
20.0°C. What is the fluoride ion concentration in ppm of the resulting solution, given that
NaF is 45.0% fluoride ion by mass, and the density of water of 1.00 kg/L? - CORRECT
ANSWER: 2.5 x 45/100 = 1.125mg
weight of ion / weight of water = ppm
so, 1.5L = 1.5 Kg
1.125mg / 1.5 kg = 0.75
,A solution is made using 163.7 g of dimethyl ether (MM = 46.07 g/mol) and 90.0 g of
methanol (MM = 32.04 g/mol). What is the mole fraction of the dimethyl ether in the
solution? - CORRECT ANSWER: find mol of dim & methanol
dim mol / dim mol + methanol = mol fraction
A solution is made using 175.7 g of hexane (MM = 86.18 g/mol) and 200.0 g of octane
(MM = 114.2 g/mol). What is the molality of the hexane in the solution? - CORRECT
ANSWER: m = (W g of solute / Molar mass of solute) (1000 / W g of solvent)
(175.7g / 86.18g/mol) ( g) = 10.19m
A theory is another word for a(n) _________. - CORRECT ANSWER: A theory or model
is a well established explanation of a phenomenon based on a series of facts and a
body of evidence.
All the following statements concerning a sample of oxygen gas at 1.00 atm pressure
are true EXCEPT
A) the molecules are in constant rapid random motion.
B) the pressure exerted by gaseous oxygen is due to the impact of the molecules with
the walls of the container.
C) the average kinetic energy of the gaseous oxygen is inversely proportional to the
absolute temperature of the gas.
D) collisions between the gaseous molecules are elastic.
E) the volume occupied by the oxygen molecules is negligible compared with the size of
the container. - CORRECT ANSWER: C) the average kinetic energy of the gaseous
oxygen is inversely proportional to the absolute temperature of the gas.
All will contribute equally. Because boiling point elevation is a colligative property, it
depends only on the concentration of solute, not the type of solute. - CORRECT
, ANSWER: Vapor pressure describes the tendency of a substance to change from the
liquid to the gas phase, so substances with weaker intermolecular forces will have
higher vapor pressures. A substance's boiling point is also indicative of the strength of
the intermolecular forces, with weaker intermolecular forces resulting in lower boiling
points. Because acetone has the lowest boiling point of the options given, it has the
weakest intermolecular forces, and will therefore have the highest vapor pressure.
Amonton's Law - CORRECT ANSWER: if the volume of a gas is held constant,
increasing the temperature of the gas increases its pressure.
An exothermic reaction causes the surroundings to - CORRECT ANSWER: An
exothermic reaction transfers energy from the system to the surroundings. That tells us
the surroundings will get warmer.
At a particular temperature, the solubility of H₂ in water is 0.140 M when the partial
pressure is 1.20 atm. What partial pressure (in atm) of H₂ would give a solubility of 4.95
M? - CORRECT ANSWER: 42.4 atm
C = kP --> c12/c1 = p2/p1
Avagadro's Law
in terms of KE - CORRECT ANSWER: Container pressure constant, more gas
molecules added = increased volume
Avogadro's Law - CORRECT ANSWER: equal volumes of gases at the same
temperature and pressure contain equal numbers of molecules
Boyle's Law
in terms of KE - CORRECT ANSWER: Volume decreased, wall area decreased =
increased pressure
